Passing tests: https://buildkite.com/ray-project/periodic-ci/builds/2560#_
Add an echo timestamp to the post build commands of the ray lightning release tests to trigger a cluster env rebuild and get the latest versions of ray lightning. Without this, the cluster env gets cached so an outdated version is installed on the cluster that is different than the one on the driver, resulting in the below failures.
Closes#21871Closes#21863
Also reinstalls the dependencies in the post build commands so old versions are not cached in the Docker images
* use nightly
* switch ml cpu to ray cpu
* fix
* add pytest
* add more pytest
* add constraint
* add tensorflow
* fix merge conflict
* add tblib
* fix
* add back uninstall